External orthopedic fixation systems having the shape of plates or rings for the use with clamps and bone are known for fracture fixation. The person skilled in the art knows such rings for example from the Illizarov Apparatus. Thereby several rings are positioned around limbs interconnected by struts and used to accommodate elements such as posts etc. which are in connection with a Kirchner wire or pin connected to a bony structure on either side of a fracture. Such rings are commonly used for wire placement or pin placement. Tensioned wires are in an engagement with said bony structure and at two circumferentially spaced positions on a single ring.
U.S. Pat. No. 5,275,598, for example, discloses a ring having several openings that are arranged in regular intervals. Thereby the wires are fixed by means of nuts and bolts with the opening of the ring. Several wires are arranged such that they extend from one side of the ring across the inner ring diameter to the other side of the ring. Consequently, the wires cross at a certain location. If the wires lie more or less in the same plane the wires have to be bent so that they avoid interference with one another. Upon tensioning of this distorted wire, an unstable force occurs at the intersection. This instability leads to bone movements and can disorient the fracture.
Some prior art devices use wire clamps which can be shifted in height in order to arrange several wires extending in several parallel planes. The use of different wire clamps is cumbersome and complicated for the medical practitioner as the height of said clamps has to be adjusted for example, to provide the separate parallel planes for each wire.
Furthermore the person skilled in the art alternatively uses a plurality of washers together with bolts and nuts in order to place wires in different planes. However, the use of such elements is rather cumbersome and complicated. Furthermore the use of bolts and nuts requires that the medical practitioner has to use two wrenches or other tools in order to tighten the bolts and the nuts.